kvm: svm/avic: Do not send AVIC doorbell to self

AVIC doorbell is used to notify a running vCPU that interrupts has been injected into the vCPU AVIC backing page. Current logic checks only if a VCPU is running before sending a doorbell. However, the doorbell is not necessary if the destination CPU is itself. Add logic to check currently running CPU before sending doorbell. Signed-off-by: Suravee Suthikulpanit <[email protected]> Reviewed-by: Alexander Graf <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
devinus · Jun 4, 2019 · 0532dd5 · 0532dd5
1 parent b6c4bc6
commit 0532dd5
Showing 1 changed file with 7 additions and 4 deletions.
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
@@ -5163,10 +5163,13 @@ static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
 	kvm_lapic_set_irr(vec, vcpu->arch.apic);
 	smp_mb__after_atomic();
 
-	if (avic_vcpu_is_running(vcpu))
-		wrmsrl(SVM_AVIC_DOORBELL,
-		       kvm_cpu_get_apicid(vcpu->cpu));
-	else
+	if (avic_vcpu_is_running(vcpu)) {
+		int cpuid = vcpu->cpu;
+
+		if (cpuid != get_cpu())
+			wrmsrl(SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpuid));
+		put_cpu();
+	} else
 		kvm_vcpu_wake_up(vcpu);
 }